SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e50cc4d4c19c5b76cb1c884936a4d79152066193792d9d23e1f26aa41379feb4' 
  AND token = '+Quz7EO/tPbzcugKYIEBqG/MMWhHZpqIgdfL3twwYV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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