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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e06a76ca4b8ac0093116fc687ec0cb2ee4aa72e4b1e29db69bccc8ecbaf1fa41' 
  AND token = '3yF8jfwPu68SIwzGNBqasJ/4HtVpfasZleqeIRJ+Qqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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