SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59c5355e16b3b4155ce0bd89802e430b100b7203fc83a134a49372462108f26c' 
  AND token = 'MjwPtpG4Zcvil/paF4wkAuBMYKNAOgEUIpJLjsz4JRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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