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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '421a5928c775e4c30d4b0a9fef7120ca38b7c171543a765b19c7b67a071c9ecd' 
  AND token = '/c5u1GnnPh4PZLWDg6u/YwW4kfZDdsg5yGs+E/8e6uQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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