SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b78993cd8044af1756fdb9b56252860273b8ef2bdd0cfdd3d17c88e79d106144' 
  AND token = 'X7TKukdcmH9sVpLAoZpQttljQ458ZF9p8X7Q6AahKDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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