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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e3e1bde507f6695d1a56815fcbe86ae626ccf7dec82f9aeb1c3afeae0694cb84' 
  AND token = '0hWz2Lmqtc8Pqvs2kjTXxm1c9s6l2bvbp5RCShfFUcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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