SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4fd43015f9939fa690163ed177908442dceabe22cf9b957d20e79c43af44f61' 
  AND token = 'TopJcl0eUDU4JEOXt1Gjh3eYEEsfupTSpIGNF3H2FNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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