SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4abae627e306fa2aedda8e1e263798ed27449420f0b3602c91919dfe0e75d577' 
  AND token = 'u3TnLkQmgZiVLNUtVNl/HCu9EWQwdpGaZy2B0DKI3mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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