SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcfe74bd5c826df4993fe60ebd2a773c5099ccfa64b96093dd45a0a51620912c' 
  AND token = '0oL4rr4PZ2f1bWF5lJacEPubvGrv/ZK8yU/dqDYjRiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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