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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '504aeb1f0f73a413beafb2a4c6f97fd8f1c8c4aaf9794faa4df4f5bf1bf313da' 
  AND token = 'upgoVq+A0xBxcXZbbpXr5pkhfJhdMdsUklN6XsJjk8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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