SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f59c85d041e74951e814173ebeae8d3da2514cacb359994733ea4e23cdbbca50' 
  AND token = 'mpUsuavenZEGlKZYmB/K2rxEHXOadu8X2w26omZF0DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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