SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1eb32589a5c6d8920c708ecd25ca9e84bde40e07381c2679c200c84a01c818b1' 
  AND token = 'PHEgZy1X5EIuSfTlRbvxg36nzY0m1qgMCdUHkKhVT9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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