SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bbceca3d535fc5dd253c120181f8f0d754dfa304789157d7dc2e9314052ce91' 
  AND token = '3Hy93+RHWgyrw95OJfpHRPDVihu4LDa4a8dQPV8IvuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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