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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c1df05b10932a39ffaa47f64852b1d35fa9162ad2afd00b0e7a5cbc266dcaf' 
  AND token = '/Z3Lk6s0rB7W+DufEZydxSCQr1YfzXYv2ylsyNqaH9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}