SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd54d3a772c23ae97ba73988e8389adbbf7efe61fdb64529ffd981eb418993cb' 
  AND token = 'c8Mm7VdtMXuIkj3JEbqAj0BlxW02CyKpPsK7CB8ZXrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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