SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8252af102e3926ae5629a12aebc4aab5baec1cb960ddf72570400b4c94b56b1' 
  AND token = 'K+SzGhbZCDevZlQqdgNWMz4yccdsoL+9k7M+NN5Tbw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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