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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b4e5ad6dadff3fdb5da03e7dacb8d06061ea4b8f6292e38bad9d2df9e836a65' 
  AND token = 'll9cdB8AXUm44AtowJD3Hqqq4EXpwMYsQfXDamviPvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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