SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f1e5026370594db7ce8a28ad592aeef2aaeddce6d9bdb7122f122c07826754' 
  AND token = 'PL2cXHUz26vvZiFEBggUtulloW2LUaFvTq2B8KHffyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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