SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '925a3247b4889d687201f2a94596fec1f06d502d5f3c03feb81bb5444d333443' 
  AND token = '7m+UDhQsjWo0Xye/JKQmsdHCtw0mij0st3vaV8tVjB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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