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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb31b92e3dc2df487683363851d14b590ac1630ee9df1089781a1a4ebf4f42fb' 
  AND token = 'E3zjBDQ17U2PGvTwWTEoEzYFI5wP6+JT1JE20bkSC4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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