SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e595dbef8f9efc3a615320aee3b0a8645cd4391808ec51ac0a87e8075840d01c' 
  AND token = 'oMa6RsjPbSoCH0I9u7R+JoCbjf+IfXvpdVRFVyaNIMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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