SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4c40de7405321af57341636bcd36dfe42dd0a0aad8b77fc5273b20ccca791c03' 
  AND token = 'CovqNcnLMaiEP0bNBb40OLeqAfAdDe86trCJ09q/mNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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