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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7cbb51460d910281cbde4a2c0383ab576bdd00526e00f2f6027a1ddb2e8f171' 
  AND token = 'ZXxA8xw/BnwAoRCsVagbRXnE1POHINdIG1hyvIi3o5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}